基于体素锥追踪的全局光照算法  

Global Illumination Algorithm Based on Voxel Cone Tracing

作　　者：桂梅书 侯进[1] 谭光鸿 吴佩军 Gui Meishu;Hou Jin;Tan Guanghong;Wu Peijun(School of Information Science and Technology,Southwest Jiaotong University,Chengdu,Sichuan 611756,China)

机构地区：[1]西南交通大学信息科学与技术学院

出　　处：《光学学报》2019年第6期284-293,共10页Acta Optica Sinica

基　　金：浙江大学CAD&CG国家重点实验室开放课题(A1923);成都市科技项目(2015-HM01-00050-SF)

摘　　要：提出一种全局光照的计算方法,使用体素结构存储简化场景的光照信息,并通过体素锥追踪方法来收集光照信息,计算间接光照。在计算过程中,每帧只更新动态场景的体素结构,既可以支持动态光源,又避免了更新静态场景的时间消耗。通过各向异性过滤生成的方向性层级结构,将简化的体素场景及光照信息压缩存储在三维纹理的渐近贴图中,从而减少存储开销。利用体素锥追踪收集体素结构中存储的出射辐射度及遮蔽值来计算环境遮蔽、软阴影等全局光照效果。实验结果表明,所提方法可计算多种全局光照效果,并具有较好的绘制效率,在复杂的场景下单帧时间少于33.3 ms。In this study, we propose a global illumination algorithm based on the voxel structure. In the proposed algorithm, the voxel structure is used to store the illumination information of a simplified scene, and the indirect illumination effects can be obtained by collecting the illumination information using the voxel cone tracing method. Only the voxel structure of the dynamic scene is updated in each frame, which supports dynamic light sources and avoids unnecessary calculations for updating the static scene. The voxel structure is a directional hierarchical structure generated by anisotropic filtering, which can be compressed and stored in a mipmapped three-dimensional texture, reducing the storage costs. It is possible to calculate the global illumination effects, such as ambient occlusion and soft shadow, by collecting the outgoing radiance and occlusion values stored in the voxel structure using the voxel cone tracing method. The experimental results demonstrate that this approach can obtain various global illumination effects and exhibit a decent rendering efficiency. Furthermore, the single-frame time is less than 33.3 ms in case of complex scenes.

关 键 词：光计算 光学数据处理 全局光照 体素结构 体素锥追踪 间接光照 

分 类 号：O436[机械工程—光学工程]